The researchers addressed the two key issues with DNA aptamers, increasing their ability to bind to targets, while making them more difficult to digest(Credit: Shutterstock)

A team of
researchers from the Institute of Bioengineering and Nanotechnology
at the Agency for Science, Technology and Research (A*STAR) has
worked to develop an efficient technology that uses DNA to detect and
treat infectious diseases. Improving upon an existing method, the
research makes use of single-stranded DNA molecules called aptamers,
and it could be used to treat cancer.

Aptamers are
good candidates for the development of new treatments, as they have
an innate ability to bind to any molecule they're targeted at,
including cancer cells and bacteria. Once bound to a target, the aptamer inhibits its
activity, eliminating the threat it poses to the host.

While aptamers
are useful for both detecting and treating dangerous conditions, they
suffer from two issues that stop them from being as effective as they
could be. Firstly, the bonds they form with target molecules are
usually too weak to be effective, and they're easily digested by
enzymes. These two problems have been a barrier to getting aptamers
approved for clinical use.

The A*STAR
researchers decided to tackle these exact problems. Firstly, they
added an artificial component, referred to as an unnatural base, to a
standard aptamer, increasing its ability bind to target molecules. A
second addition was then made in the form of a small DNA, known as
mini hairpin DNA. With a particularly stable and compact structure,
the component is very resistant to digestion, allowing the aptamer to
reside in the system for days instead of hours.

With the two
major issues with DNA aptamers addressed, it's possible that they
could one day replace antibodies for disease targeting. Antibodies
bind to their targets in the same way as aptamers, but unlike the
pioneering DNA technology, they can give rise to undesirable immune
responses, and aren't as easy to produce in large quantities at high
quality.

"Our aptamers
are more efficient, and lower in cost and toxicity compared to
conventional methods," said team member Dr Hirao. "The next step
of our research is to use the aptamers to detect and deactivate
target molecules and cells that cause infectious diseases, such as
dengue, malaria and Methicillin-resistant Staphylococcus aureus, as
well as cancer."

The researchers addressed the two key issues with DNA aptamers, increasing their ability to bind to targets, while making them more difficult to digest(Credit: <a href="http://www.shutterstock.com/pic.mhtml?id=185401712&src=id" rel="nofollow">Shutterstock</a>)